e 99 7.3 electrical issues

my battery is at 12.0 volts when I hook it up to the the truck it drops down to 9.5. When I disconnect it, it goes back to 12.0. when it is plugged in it has a ticking noise from under the dash. It also doesn't have any power to the gauges. I have been working on it for 3 days now and I am out of ideas please HELP!!!!
Thanks

That tells me you have a dead short any idea where the ticking is which side

it was under the radio. I tried jumping it from my wifes car and the noise has now stopped. When I first turn the key the volts are at 13. While waiting for the wts light they drop down to 8. Then shortly after the fuel pump goes off they come back up. I just put a new fuel pump in and i am trying to prime it but it seems like there is not enough power to get it to flow. I have looked online and have not been able to find much. I believe the ticking was from the fuel pump relay. I have switched it out and still not keeping power. Any Ideas what could be draining on initial start up process.

Where are you located? If it's warm enough out disconnect the GPR and try it that way

Yes it is 70ish. Thanks for the tip. Latest update when i left it connected to my wifes car for approximately 30 min. it started without dropping in volts. I had the batteries tested 3 weeks ago and they said they were good. The new fuel pump I put in is not pumping I tried pressurizing the tank with a compressor but no luck. When I disconnected the fuel lines I didn't feel any suction or blowing from the new pump. What are your thoughts on that? Thanks for the help so far I cant tell you how much I appreciate it!

Welcome Mr Jones . You may have better luck posting this in the 7.3 section, or have mods move it , you may get a lot more help , good luck

Check your battery cables. If there is any swelling at the terminals, replace them.

Welcome to the site

Tony:rockon:

Welcome to PSA!

Sock filter in the tank clogged and not allowing flow?